Here’s a more appropriate video of Carl for his birthday. Here he tries to imagine the 4th dimension, but gets caught in our 3D limitations. So we are left to “think” about the 4th Dimension since we cannot “imagine” it… Now we have 11 or so dimensions that are unstable, amorphous, ever reinvented, and curled upon themselves and wrapped around all the other dimensions…I think…It’s confusing and fascinating…Do they really exist or is it just math gone batty…does it matter? It does, for reasons we don’t yet understand. And thanks to Dr. Sagan for opening up my mind to all of this. Happy B-Day again!